Neuron
Although both protein and mRNAs for kainate receptor subunits are abundant in several brain regions, the responsiveness of AMPA receptors to kainate has made it difficult to demonstrate the presence of functional kainate-type receptors in native cells. Recently, however, we have shown that many hippocampal neurons in culture express glutamate receptors of the kainate type. The large nondesensitizing...
Monoclonal antibody 31712 identifies a cytoplasmic antigen of 49 kDa in human hippocampus and neocortex. The distribution of 31712 immunoreactive neurons closely matches that of Alzheimer's disease (AD) targeted neurons in these areas. In some hippocampal neurons of AD patients, this antigen colocalizes with ALZ-50, indicating the presence of AD pathology in these neurons. Molecular characterization...
The mammalian neocortex consists of columnar circuits, whose development may be controlled by patterns of spontaneous activity. Columnar domains of spontaneously coactive neurons were previously described using Ca 2+ imaging of slices from developing rat neocortex. We have now investigated the cellular mechanisms responsible for the coactivation of these domains. The activation starts in the center...
C. elegans male mating behavior comprises a series of steps: response to contact with the hermaphrodite, backing along her body, turning around her head or tail, location of the vulva, insertion of the two copulatory spicules into the vulva, and sperm transfer. By ablation of male-specific copulatory structures and their associated neurons, we have identified sensory structures and neurons that participate...
Partial denervation or paralysis with botulinum toxin, manipulations that induce sprouting of nerve terminals in muscle, also induced terminal Schwann cells to extend processes. These processes were associated with every nerve sprout and in some cases were longer than the sprouts that appeared to be growing along them. Following partial denervation, more than 70% of the nerve sprouts that grew to...
The nucleus is surrounded by a double membrane separating it from the cytoplasm. The perinuclear space is continuous with endoplasmic reticulum, and the nuclear outer membrane shares many features with the reticular membrane. We now show that inositol 1,4,5-trisphosphate (InsP3) receptors associated with the ] nucleus release Ca2+ from isolated Xenopus laevis oocyte nuclei. Electrophysiological measurements...
Cerebellar neurons, cultured on monolayers of 3T3 fibroblasts or on a polylysine/extracellular matrixcoated substratum, responded to a soluble recombinant L1-Fc chimera by extending longer neurites than controls. The response was inhibited by pretreating neurons with antibodies to Ll or antibodies to the fibroblast growth factor (FGF) receptor. The response could also be inhibited by a range of pharmacological...
Agonist binding to the inhibitory glycine receptor (GlyR) initiates the opening of a chloride-selective channel that modulates the neuronal membrane potential. Point mutations of the GIyR, substituting Arg271 with either Leu or Gin, have been shown to underlie the inherited neurological disorder startle disease (hyperekplexia). We show that these substitutions result in the redistribution of GIyR...
In lamprey spinal cord, intracellular calcium ([Ca 2+]i) plays a key role in mechanisms regulating neuronal activity in the segmental network for locomotion. In this report, measurements of [Ca 2+]i with fluo-3 in various regions of motoneurons in the intact spinal cord were obtained on a high speed confocal microscope following electrical stimulation. Likewise, rhythmic calcium fluctuations within...
The modulation of voltage-activated Cat+ channels by neurotransmitters and peptides is very likely a primary means of regulating Ca 2+-dependent physiological functions such as neurosecretion, muscle contraction, and membrane excitability. In neurons, N-type Ca2+ channels (defined as ω-conotoxin GVIA-sensitive) are one prominent target for transmitter-mediated inhibition. This inhibition is widely...
The aim of this study is to gain insight into the time during the life history of a retinal neuron that it becomes committed to a particular phenotype. At this point, it is not possible to identify the time of commitment, but the time that differentiation begins can be identified. Bromodeoxyuridine labeling coupled with immunohistochemistry with a ganglion cell-specific antibody was used to fix the...
Ion channels directly activated by the binding of cGMP mediate the electrical response to light in rod photoreceptors. Here, we identify a region of the channel associated with the activation gate using potentiation by intracellular Ni2+. Low concentrations of Ni2+ caused a dramatic increase in the response of rod channels expressed in Xenopus oocytes to both cGMP and cAMP. Whereas saturating cAMP...
Early olfactory axons follow a specific pathway to reach the developing telencephalon. We observed that a subpopulation of these axons, the pioneer olfactory axons, penetrate into the ventricular zone of a highly restricted region of the telencephalon at E13 and E14. At E15, this same telencephalic region evaginates to form the olfactory bulb. To investigate the possibility that the pioneer olfactory...
Terminal Schwann cells overlying the neuromuscular junction sprout elaborate processes upon muscle denervation. We show here that motor axons use these processes as guides/substrates during regeneration; in so doing, they escape the confines of endplates and grow between endplates to generate polyneuronal innervation. We also show that Schwann cells in the nerve provide similar guidance. Axons extend...
ARIA, heregulin, neu differentiation factor, and glial growth factor are members of a new family of growth and differentiation factors whose effects have been assayed on Schwann cells, skeletal muscle cells, and mammary tumor cell lines. To gain insight into their roles in the CNS, we studied the expression of ARIA in the rat brain. We found ARIA mRNA in all cholinergic neurons throughoutthe CNS,...
Ca2+-calmodulin (CaM) function was selectively disrupted in a specific subset of growth cones in transgenic Drosophila embryos in which a specific enhancer element drives the expression of the kinesin motor domain fused to a CaM antagonist peptide (kinesin-antagonist or KA, which blocks CaM binding to target proteins) or CaM itself (kinesin-CaM or KC, which acts as a Ca 2+-binding protein). In both...
Glial fibrillary acidic protein (GFAP) is an intermediate filament protein specifically expressed in astrocytes in the CNS. To examine the function of GFAP in vivo, the Gfap gene was disrupted by gene targeting in embryonic stem cells. Mice homozygous for the mutation were completely devoid of GFAP but exhibited normal development and showed no obvious anatomical ab normalities in the CNS. When inoculated...